1. Field of the Invention
The present invention relates to a one-way clutch of the shell type.
2. Description of the Prior Art
There is known a one-way clutch of the type above-mentioned disclosed by, for example, U.S. Pat. No. 3,863,742 in which the retainer includes longitudinally (axially) spaced rims (40, 42), one or more resilient spring bars (44) for interconnecting the rims and rollers (38) disposed in pockets formed by the resilient spring bars, the retainer being fitted to a case (32) provided on the inner peripheral surface thereof with ramps (34) and stops (36). The resilient spring bars operate to retain the rollers in the retainer and to resiliently bias the rollers in one direction. Tabs (48, 50) engage the stops of the case.
There is also known a one-way clutch of the type above-mentioned disclosed by U.S. Pat. No. 3,537,555 which comprises: an outer ring (1) provided on the inner peripheral surface thereof with camming gripping surfaces (2); a cage (4) made, by bending both sides thereof, in the form of a groove having an U-shaped cross section at the bottom of which openings (5) are formed, a plurality of projections (4a', 4b') being formed at the both side flanges or end rings (4a, 4b) of the groove, the cage (4) being engaged with the gripping surfaces (2) formed on the inner peripheral surface of the outer ring (1); and a strip (6) sticked to the reverse side of the cage and including a connecting piece (9) having tongue-like spring elements (8) and openings (7) identical with the openings of the cage.
As the retainer of a one-way clutch of the type above-mentioned, there is known a retainer disclosed by U.S. Pat. No. 3,500,977 in which rings (14, 15) spaced at regular intervals are connected together by a plurality of cross bars (16), which form pockets (17) in which rollers (13) are housed, each cross bar (16) being provided at both ends and the center thereof with lugs (18, 20), the lugs at the both ends having arcuate surfaces which follow the arcuate surfaces of the rollers, an oval spring (12) being engaged with each center lug.
There is also known a one-way clutch of the type above-mentioned which is disclosed by U.S. Pat. No. 3,404,760 or 3,184,020.
Also, there is known a one-way clutch of the type above-mentioned as shown in FIGS. 8 to 10, for example. This one-way clutch comprises a plurality of rollers 30, a retainer 32 having roller pockets 31 in the same number as that of the rollers 30, a shell 34 having cam grooves 33 in the same number as that of the rollers 30, and springs (not shown) for biasing the rollers 30 toward the cam grooves 33.
This one-way clutch is made by the steps of radially inwardly bending one open end of a case body to prepare an unfinished shell 34 having a radially inwardly turned flange 34A, putting the rollers 30, the springs and the retainer 32 in the shell 34 through the open end thereof, and radially inwardly bending the open end of the shell 34. Thus, the one-way clutch is arranged such that the retainer 32 and other component elements do not come off from the shell 34. The cam grooves 33 are formed substantially throughout the axial length of the shell 34, and gaps D are formed, as shown in FIGS. 9 and 10, between the inner peripheral surfaces of the cam grooves 33 and the outer peripheral surfaces of the annular portions at the axial ends of the retainer 32. Accordingly, grease in the spaces where the rollers are present, may leak outside through the gaps D. In this connection, both ends of the shell 34 are radially bent to close the gaps D, thereby to prevent the leakage of grease.
There is also known a one-way clutch as shown in FIG. 11. This one-way clutch is different from the one-way clutch shown in FIGS. 8 to 10 in that one end of the shell 34 is not bent but remains opened axially straight. The open end of the shell 34 is adapted to be closed by a radially inwardly turned flange 35A provided at the inner part of the housing space of a housing 35 on which the one-way clutch is mounted.
In the one-way clutch shown in FIGS. 8 to 10, there is required a bending operation for radially inwardly bending one open end of the unfinished shell 34. If the shell 34 is one cured by heat treatment, it is difficult to bend the open end thereof. Thus, the working efficiency is low to disadvantageously increase the production cost.
In the one-way clutch shown in FIG. 11, before the component elements housed inside of the shell 34 are assembled with the housing 35, the component elements might come off, thus presenting inconvenience to handling before the clutch is assembled with the housing 35.
As a retainer to overcome the problems above-mentioned, there is known a retainer disclosed by Japanese Utility Model Laid-Open Publication No. 43532/1990 or 110724/1990. In this retainer (2, 1), one annular portion (21, 3) is provided on the circumference thereof with projections (25, 31) at regular spatial intervals, the other annular portion (22, 2) is provided with a convex engagement portion (5, 21), and V-shape elastic pieces (24, 6) are disposed for pushing, in one direction, rollers disposed in roller pockets (20, 5) from column portions (23, 4).